Data-Driven Determination of the Light-Quark Connected Component of the Intermediate-Window Contribution to the Muon $g-2$

We present the first data-driven result for $a_{\mu }^{\mathrm{win},\mathrm{lqc}}$, the isospin-limit light-quark connected component of the intermediate-window Hadronic-vacuum-polarization contribution to the muon anomalous magnetic moment. Our result, $(198.8\pm 1.1)\times {10}^{-10}$, is in significant tension with eight recent mutually compatible high-precision lattice-QCD determinations, and provides enhanced evidence for a puzzling discrepancy between lattice and data-driven determinations of the intermediate-window quantity, one driven largely by a difference in the light-quark connected component.

Figure 1

Comparison of our final result (BBGKMP 23), Eq. (17), with lattice results for $a_{\mu }^{\mathrm{win},\mathrm{lqc}}$ from [32] (BMW 20), [41] (LM 20), [42] ($\chi \mathrm{QCD}$ 23), [43] (ABGP 22), [34] (Mainz-CLS 22), [35] (ETMC 22), [44] (FHM 23), and [36] (RBC-UKQCD 23).